Bucket position indicator



July 21, 1964 s. A. FISHER BUCKET POSITION INDICATOR 2 Sheets-Sheet 1 Filed July 10,1962

ATTORNEY July 21, 1964 e. A. FISHER BUCKET POSITION INDICATOR 2 Sheets-Sheet 2 Filed July 10. 1962 angry i221 5% United States Patent 3,141,563 BUCKET POSITION INDICATGR George A. Fisher, Mentor-on-the-Lalre, Ohio, assignor to General Motors Corporation, Detroit, Mich, a corporation of Delaware Filed July 10, 1962, Ser. No. 208,832 6 Claims. (Cl. 214140) This invention pertains to a position indicating mechanism for indicating a selected position for the material handling bucket of a front end loader vehicle.

One example of a bucket position indicator of the type this invention relates to can be found in a patent to Runci et al. 3,017,046, assigned to the assignee of this invention. The device covered by Runci et al. comprises a mechanism having a pointer that is movable relative to an indicia so as to indicate to the vehicle operator the position of the bucket with respect to the boom and associated linkage. Thus, where the boom is in a fully raised or any intermediate position, the vehicle operator is able to pre-position the bucket so that the latter automatically assumes a dig position upon fully lowering the boom.

The present invention is directed to an improved bucket position indicator of the above-described type that is of simple and durable construction and characterized by having the pointer pivotally mounted to the piston rod pin of the hydraulic jack. An upstanding projection is fixed to the piston rod to cooperate with one end of the pointer for indicating the relative positions of the piston rod and cylinder of the hydraulic jack. The opposite end of the pointer is formed as a cam follower and is adapted to engage a cam surface secured to the cylinder so that upon contraction of the jack, a camming action occurs with resultant movement of the pointer.

The features of this invention as well as the manner in which they are attained will become more apparent hereinafter as the description of the invention proceeds with reference being made to the following drawings in which:

FIGURE 1 is a side elevation of a front end loader vehicle with parts broken away to illustrate certain details of the invention,

FIGURE 2 is a fragmentary enlarged view of FIG- URE 1 illustrating certain details of the bucket positioning mechanism,

FIGURE 3 is a view on line 33 of FIGURE 2,

FIGURE 4 is a view of a modified form of the bucket positioner of FIGURE 2,

FIGURE 5 is a view taken on line 5-5 of FIGURE 4, and

FIGURE 6 is a view taken on line 66 of FIGURE 4.

Referring now to FIGURE 1, there is shown a portion of a rubber-tired loader vehicle 2 having an operators station 4 and a loader support and linkage mechanism 6 disposed at the front end of the vehicle. It will be readily apparent to those skilled in the art that that portion of the loader support mechanism and linkage associated with the left side of the vehicle is shown in FIGURE 1 of the drawings, it being understood that identical structure is associated with the right side of the vehicle. Accordingly, reference will only be made to the structure on the left side of the vehicle.

A support pillar 8 is rigidly secured to the frame structure of the vehicle and includes an upwardly extending pillar or post portion 10 and a similar downwardly extending post portion 12. The loader boom 14 has its rearward end pivotally connected at 16 to the pillar portion 10 and extends forwardly and downwardly in front of the front vehicle axle. A bucket 18 is pivotally connected at 20 to the forward end of the boom structure 14 and includes ice transversely spaced side walls 22 joined by a bottom wall 24, and a cutting edge 26 extending along the forward edge of the bottom wall at the front of the bucket. A boom lifting jack or hoist 28 has one end pivotally connected at 39 to the lower pillar portion 12 and its other end pivotally connected at 32 intermediate the ends of the boom 14.

The bucket tilt linkage is of the distorted parallelogram type and includes a tilt lever 34 pivotally connected at 36 to the boom. A rigid link 38 is pivotally connected at 40 to the upper end of the tilt lever 34- and at 4-2 to the upper pillar portion 10. A double acting hydraulic hoist or jack 44 has one end pivotally connected at 46 to the lower end of the tilt lever 34 while the other end of the hoist is pivotally connected at 48 to the bucket 18.

It will be readily appreciated that a suitable hydraulic system including a manual selector valve is employed to selectively supply fluid to the lower ends of the boom jacks 28 to elevate the boom structure. Ordinarily, the boom jacks are of the single acting variety inasmuch as gravity is relied upon for returning the boom structure to its lower position as shown in the drawing. The tilt jack 44 is double acting so as to be extensible and retractable from the position shown in the drawing to position the bucket as required.

In the operation of a loader mechanism of this type, it will be understood that the tilt jack 44 may be selectively extended and contracted to dispose the bucket 18 in any one of several positions. For example, in the position shown in FIGURE 1, the jack 44 is in an intermediate position, disposing the bucket 18 in a low level digging position in which the forward portion of the bottom wall 24 of the bucket is disposed substantially horizontal or parallel to the ground. After digging in this position, the hoist 44 may be contracted substantially all the way to pivot the bucket 1$ clockwise about the pivot point 25 to the low level load retaining position. Thereafter, the boom jack 28 may be extended to move the boom to a high lift position. At this time, the tilt jack 44 may be extended substantially all the way to pivot the bucket about the pivot point 20 to a high lift dumping position.

From the above description of the loader operation, it

may be said that such a loader mechanism has two extreme bucket positions; that is, at low level load retaining position in which the hoist 44 is substantially fully contracted, and the high lift dumping position in which the hoist is substantially fully extended. The aforementioned digging position, as shown in FIGURE 1 of the drawings, is intermediate these two extreme bucket positions. With the bucket in a low level position, it is quite difficult for the vehicle operator to dispose the bucket in such a digging position inasmuch as he has an obstructed view of the bucket.

The distorted parallelogram type tilt linkage aforedescribe'd has found considerable favor in the earth working trade because it automatically functions to maintain the bucket in a load holding attitude as the support booms are elevated. For example, assuming that a load has been received in the bucket, the tilt jack 44 may be retracted to the low level load retaining position at which time the bucket is rolled rearwardly a small amount about the pivot point 20. As the boom hoist 28 is extended, the geometry of the tilt linkage serves to automatically roll the bucket forwardly about the pivot point 20 so as to maintain the bucket in a non-spilling attitude; that is, a position in which the mouth of the bucket is maintained substanially horizontal or parallel with the ground. In some linkage structures, the distorted parallelogram construction not only serves to maintain the bucket in a non-spilling attitude, but is also employed to initially roll the bucket rapidly rearwardly upon breaking the bucket from the load at the low lever digging position. Irrespective of whether or not the tilt linkage 1S employed for one or the other or both of these functions, and as is well known in the art, it should be noted that relative movement between the bucket and boom structure is relatively drastic, particularly in the lower range of boom movement.

Referring now to FIGURES 2 and 3, the bucket position indicating mechanism St) may be seen to comprise a cam bracket 52 rigidly connected to the forward end of the cylinder 53 of the tilt jack 44 and having a curved camming surface 54 which extends forwardly and slightly below the end of the cylinder. The camming surface is disposed in a substantially vertical direction and terminates at the lower end thereof with a straight guide edge 55. The cam bracket 52 is in the form of an angle iron with the transverse flange 56 being bolted to the cylinder while the portion lying in the plane of the drawing is disposed parallel to the bucket side walls 22. The apertured head 57 of the tilt jack piston rod 58 supports the transverse pivot pin 48 connected to the upper end of the bucket 18. The pin, in turn, rotatably supports a pointer 60 substantially intermediate the ends thereof so as to divide the latter into upper and lower portions, 62 and 64 respectively.

As best seen in FIGURE 3, a stop member 65 is fixed to the pointer upper portion 62 and extends laterally therefrom for cooperation with a cylindrical extension 68 lying on the longitudinal aXis of the piston rod. As should be apparent, a coil spring 69 secured between the pointer 60 and the piston rod head 57, by the respective lugs 7t) and 71, continuously urges the pointer in counterclockwise 7 direction about pin 48 as limited by the cooperating stop from one corner of the upper portion 62 and a laterally projecting tongue or cam follower 74 formed with the lower portion 64 for cooperation with the camming surface 54 of the cam bracket 52. An upstanding projection 76 is attached, such as by welding, to the piston rod head 57, and can be formed from a thick rigid wire with the free end thereof bent laterally towards the pointer 60. The projection '76 serves as an indicia so that when the pointer arm 72 is in alignment with the former as shown in the intermediate view of FIGURE 2, this indicates to the operator that the bucket 18 is in the proper position for assuming a level or digging position when the boom is fully lowered.

In operation, when the bucket is in the low-level digging position as shown in FIGURE 1, the tilt jack may be contracted to place the bucket in the low-level load retaining position as mentioned before. During such retraction, the pointer 60 is moved rearwardly with the piston rod head 57, during which time the cam follower '74 slides along on the cam surface 54 to rotate the pointer clockwise about pin 4-8 until it leaves the cam surface to ride along the guide edge 55. When the jack is completely retracted, the relative positions of the several elements would be as shown in full lines in FIGURE 2, at which time the pointer arm 72 is located between the projection 76 and the end of the cylinder 53.

Thereafter, the boom jacks 28 may be actuated to elevate the booms 14 to a high lift position. During this movement, the bucket 18 will be lowered automatically about the pivot point 2b to maintain the bucket in a nonspill attitude with respect to the ground. In order to dump the bucket at the high lift position, the jack 44 is extended its full length causing the cam follower 74 to move along the guide edge 55 and progressively along the curved cam surface 54, at which time the pointer rotates clockwise about its pivot axis under the influence of spring 69. When the cam follower leaves contact with the camming surface 54, further clockwise movement of the pointer 60 is restrained by the cooperating stop members 66 and 68. At this time, the pointer arm 72 will be forward of the projection 76 and will indicate to the operator that the bucket is similarly in a forward or dumping position.

After dumping a load, the tilt jack is contracted by the vehicle operator. As the piston rod retracts into the cylinder of the jack, contact between the cam follower 74 and the camming surface 54'occurs when the relative positions of the parts are as shown in the most forward phan .tom line view of FIGURE 2. Continued contraction of the jack causes the tongue to slide along the cam surface and when the pointerarm 72 is vertically aligned with the projection 76, the vehicle operator is thereby signaled that the bucket is in a position whereby a mere lowering of the boom will cause the parallel linkage to dispose the bucket in a level or digging position. Hence, the bucket positioning mechanism is such that it gives an accurate indication of a bucket digging position irrespective of the elevation of the boom. In other words, such indication is related fully to the length of the tilt jack so that the bucket can be positioned as desired at any boom elevation. Therefore, this mechanism is particularly adapted for use in a parallelogram type tilt linkage as disclosed herein because it gives an accurate indication of the digging position'at high lift elevation of the boom even though the linkage causes irregular movement of the bucket relative to the boom in lowering and raising the boom.

FIGURES 4 through 6 show a modification of the above described device in which corresponding numerals are used to indicate corresponding parts. This mechanism primarily differs from that disclosed in FIGURES 1 through 3 in that the pointer 60 is formed with a cam follower 74 in the form of a transverse plate that is connected by an inclined portion 78 to a pair of triangular side walls 80. The side walls, in turn, are pivotally sup- 4 ported by a bucket mounting coller 82 which is held rigid with the piston rod 58 by the pin 48. The cam follower terminates at its upper end with a transversely extending edge 84 and upon contraction of the jack 44, it engages an elongated circular rod 86 fixed to the forward end of the cylinder with its longitudinal axis parallel to the longitudinal axis of the piston rod. Thus, as shown in FIG- URE 4, assuming the piston rod is fully extended to the left, as the jack is contracted, the cam follower 74 engages the end of the rod 86 and progressively slides thereagainst so as to rotate the pointer 60 in a clockwise direction about the axis of pin 48. When the pointer arm or tip 72 is in alignment with the projection as shown by the intermediate view in phantom lines, the relative positions of the piston rod and cylinder are such that the bucket is in the level or ground digging position. Further contraction of the jack causes the cam follower portion 78 to engage the rod 86 so that the pointer 6%) is further rotated until the edge 84 contacts the lower surface of the rod. Thereafter, the edge 84 rides on the under side of the rod to the position shown in full lines in FIGURE 4, at which time the pointer is in a substantially vertical position. As with the preferred embodiment, the spring 69, connected between the pointer 60 and the piston rod head 57, continuously urges the pointer in a counterclockwise direction aslimited by the cooperating stop members 66 and 68.

As should be apparent, upon extension of the jack, the vehicle operator is able to pre-position the bucket in ac cordance with the relative positions of the pointer arm 72 with respect to the projection 76 and thereby achieve either a level or any other desired position of the bucket in any location of the boom.

Although only two forms of the invention have been shown and described, it should be apparent that various changes and alterations can be made in this structure without departing from the spirit of the invention. Therefore, it should be understood that such changes and modifications are contemplated by the inventor and he does not wish to be limited except by the scope of the following claims.

I claim:

1. A mechanism for indicating the length of a fluid pressure operated jack including relatively reciprocable piston and cylinder members, said piston having a rod terminating with a portion adapted to accommodate a pivot pin on a transverse axis, said mechanism comprising a pointer pivotally mounted about the pivot pin, an upstanding projection rigidly secured to said one of said members adjacent the pointer and adapted to serve as an indicia, one end of said pointer cooperating with said projection to indicate jack length, follower means at the other end of the pointer, a spring connected between said portion and the pointer to urge the latter in one direction, and cam means supported on the cylinder and including an elongated rod parallel to the longitudinal axis of the cylinder and engageable with the follower means upon extension and retraction of the jack to pivot the pointer relative to the projection.

2. A mechanism for indicating the length of a fluid pressure operated jack including relatively reciprocable piston and cylinder members, said piston having a rod terminating with a portion adapted to accommodate a pivot pin on a transverse axis, said mechanism comprising a pointer pivotally mounted about the pivot pin, an upstanding projection rigidly secured to said one of said members adjacent the pointer and adapted to serve as an indicia, one end of said pointer cooperating with said projection to indicate jack length, follower means laterally extending from the other end of the pointer, a spring connected between said portion and the pointer to urge the latter in one direction, and cam means supported on the cylinder and including a curved cam surface engageable with the follower means upon extension and retraction of the jack to pivot the pointer relative to the projection.

3. A mechanism for indicating the length of a fluid pressure operated jack including relatively reciprocable piston and cylinder members, said piston having a rod terminating with a portion adapted to accommodate a pivot pin on a transverse axis, said mechanism comprising a pointer pivotally mounted about the pivot pin, an upstanding projection rigidly secured to said one of said members adjacent the pointer and adapted to serve as an indicia, one end of said pointer cooperating with said projection to indicate jack length, follower means laterally extending from the other end of the pointer, a spring connected between said portion and the pointer to urge the latter in one direction, cooperating stop means formed on said portion and the pointer to limit movement of the pointer in the opposite direction, and cam means supported on the cylinder and including a curved cam surface engageable with the follower means upon extension and retraction of the jack to pivot the pointer relative to the projection.

4. In a loader vehicle, the combination comprising a vertically adjustable boom pivoted at one end to said vehicle, a material-handling bucket pivoted at the other end of said boom, a tilt linkage operatively connected between said vehicle and bucket for tilting the latter about said boom, said tilt linkage comprising a fluid-operated jack including relatively reciprocable piston and cylinder members, said piston member being connected to said bucket about a transverse pivot axis at a point spaced from said other end of the boom, mechanism for indicating the digging position of said bucket at any boom elevation, said mechanism comprising a pointer mounted to said piston member for pivotal movement about said transverse axis, an upstanding projection rigidly secured to said piston member adjacent the pointer and adapted to serve as an indicia, one end of said pointer cooperating with said projection to indicate jack length, follower means at the other end of the pointer, a spring connected betwen said piston member and the pointer to urge the latter in one direction, stop means on the pointer and cooperating with said piston member to limit movement of said pointer in the opposite direction, and cam means supported on said cylinder member and located in a vertical plane, said cam means being engageable with the follower means upon extension and retraction of the jack to pivot the pointer relative to the projection.

5. In a loader vehicle, the combination comprising a vertically adjustable boom pivoted at one end to said vehicle, a material-handling bucket pivoted at the other end of said boom, a tilt linkage operatively connected between said vehicle and bucket for tilting the latter about said boom, said tilt linkage comprising a fluid-operated jack including relatively reciprocable piston and cylinder members, said piston member being connected to said bucket about a transverse pivot axis at a point spaced from said other end of the boom, mechanism for indicating the digging position of said bucket at any boom elevation, said mechanism comprising a pointer mounted to said piston member for pivotal movement about said transverse axis, an upstanding projection rigidly secured to said piston member adjacent the pointer and adapted to serve as an indicia, one end of said pointer cooperating with said projection to indicate jack length, follower means laterally extending from the other end of the pointer, a spring connected between said piston member and the pointer to urge the latter in one direction, stop means on the pointer and cooperating with said piston member to limit movement of said pointer in the opposite direction, and cam means supported on said cylinder member and including a cam surface located in a vertical plane, said cam surface being engageable with the follower means upon extension and retraction of the jack to pivot the pointer relative to the projection.

6. In a loader vehicle, the combination comprising a vertically adjustable boom pivoted at one end to said vehicle, a material-handling bucket pivoted at the other end of said boom, a tilt linkage operatively connected between said vehicle and bucket for tilting the latter about said boom, said tilt linkage comprising a fluid operated jack including relatively reciprocable piston and cylinder members, said piston member being connected to said bucket about a transverse pivot axis at a point spaced from said other end of the boom, mechanism for indicating the digging position of said bucket at any boom elevation, said mechanism comprising a pointer mounted to said piston member for pivotal movement about said transverse axis, an upstanding projection rigidly secured to said piston member adjacent the pointer and adapted to serve as an indicia, one end of said pointer cooperating with said projection to indicate jack length, follower means at the other end of the pointer, a spring connected between said piston member and the pointer to urge the latter in one direction, stop means on the pointer and cooperating with said piston member to limit movement of said pointer in the opposite direction, and cam means supported on said cylinder member and including an elongated rod parallel to and located below the longitudinal center axis of the cylinder and engageable with the follower means upon extension and retraction of the jack to pivot the pointer relative to the projection.

References Cited in the file of this patent UNITED STATES PATENTS 1,795,406 Nash Mar. 10, 1931 2,589,896 Toland Mar. 18, 1952 2,704,047 Lushenko Mar. 15, 1955 2,812,595 Drott Nov. 12, 1957 3,017,046 Runci et a1. Jan. 16, 1962 

4. IN A LOADER VEHICLE, THE COMBINATION COMPRISING A VERTICALLY ADJUSTABLE BOOM PIVOTED AT ONE END TO SAID VEHICLE, A MATERIAL-HANDLING BUCKET PIVOTED AT THE OTHER END OF SAID BOOM, A TILT LINKAGE OPERATIVELY CONNECTED BETWEEN SAID VEHICLE AND BUCKET FOR TILTING THE LATTER ABOUT SAID BOOM, SAID TILT LINKAGE COMPRISING A FLUID-OPERATED JACK INCLUDING RELATIVELY RECIPROCABLE PISTON AND CYLINDER MEMBERS, SAID PISTON MEMBER BEING CONNECTED TO SAID BUCKET ABOUT A TRANSVERSE PIVOT AXIS AT A POINT SPACED FROM SAID OTHER END OF THE BOOM, MECHANISM FOR INDICATING THE DIGGING POSITION OF SAID BUCKET AT ANY BOOM ELEVATION, SAID MECHANISM COMPRISING A POINTER MOUNTED TO SAID PISTON MEMBER FOR PIVOTAL MOVEMENT ABOUT SAID TRANSVERSE AXIS, AN UPSTANDING PROJECTION RIGIDLY SECURED TO SAID PISTON MEMBER ADJACENT THE POINTER AND ADAPTED TO SERVE AS AN INDICIA, ONE END OF SAID POINTER COOPERATING WITH SAID PROJECTION TO INDICATE JACK LENGTH, FOLLOWER MEANS AT THE OTHER END OF THE POINTER, A SPRING CONNECTED BETWEN SAID PISTON MEMBER AND THE POINTER TO URGE THE LATTER IN ONE DIRECTION, STOP MEANS ON THE POINTER AND COOPERATING WITH SAID PISTON MEMBER TO LIMIT MOVEMENT OF SAID POINTER IN THE OPPOSITE DIRECTION, AND CAM MEANS SUPPORTED ON SAID CYLINDER MEMBER AND LOCATED IN A VERTICAL PLANE, SAID CAM MEANS BEING ENGAGEABLE WITH THE FOLLOWER MEANS UPON EXTENSION AND RETRACTION OF THE JACK TO PIVOT THE POINTER RELATIVE TO THE PROJECTION. 